20565740820 has 96 divisors (see below), whose sum is σ = 61002160128. Its totient is φ = 5158991872.

The previous prime is 20565740813. The next prime is 20565740827. The reversal of 20565740820 is 2804756502.

It is an interprime number because it is at equal distance from previous prime (20565740813) and next prime (20565740827).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20565740827) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2743117 + ... + 2750603.

It is an arithmetic number, because the mean of its divisors is an integer number (635439168).

Almost surely, 2^20565740820 is an apocalyptic number.

20565740820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20565740820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30501080064).

20565740820 is an abundant number, since it is smaller than the sum of its proper divisors (40436419308).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20565740820 is a wasteful number, since it uses less digits than its factorization.

20565740820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10209 (or 10207 counting only the distinct ones).

The product of its (nonzero) digits is 134400, while the sum is 39.

The spelling of 20565740820 in words is "twenty billion, five hundred sixty-five million, seven hundred forty thousand, eight hundred twenty".